OT: Slinky Question

The other interesting part is the longterm stability of the slinky itself. If it can reach too far, it might wander out on progressive steps, trip on an edge, and tumble. If it's too short, it may land on the same step it's on, and die there. I suppose it has to have a step distance slightly below the tread width and occasionally brush a riser to apply some longterm centering stability. There are lateral stability issues, too.

Is a slinky ever longterm stable walking down stairs?

John

Hang on -- a conundrum is a riddle in which a fanciful question is answered by a pun. Like:

"How is a cat's tail like a long road?"

"Because they are both `fur' to the end."

We got the fanciful question part. Now we need the punnish answer. /Then/ we'll have a conundrum.

On Sat, 06 Mar 2004 14:03:35 -0600, John Fields Gave us:

Or transferred, as in this case. Kinetic energy, and altitude are the factors.

There are dynamically stable mechanical walking machines that walk and run downhill, no battery, electronics or FCS required. They could probably be dressed up for an interesting spectacle.

I read in sci.electronics.design that Mike Rocket J. Squirrel Elliott wrote (in ) about 'OT: Slinky Question', on Sat, 6 Mar 2004:

OK. The answer is 'I'll take steps to find out.'.

Yep. A very crude bang-bang controller. In principle you should be able to tune the speed of the elevator to keep the Slinky in more or less the same place - it is effectively an oscillator, so that analogy would be with a phase-locked loop rather than a simple analog control loop.

In any event it begs the question of how you reliably detect where the Slinky is. I suppose it is optically dense enough that a photo-detector would work - I'd think in terms of two bright, fairly narrow beam leds, one on either side of the escalator, and two pairs of photo-dectors, about twice the Slinky diameter apart, on either side of the escalator, flanking the leds.

---------- Bill Sloman, Nijmegen

No, it will probably get caught in the big crunch or great chill. Alternatively, someone will trip over it, thereby rendering it no longer a slinky, and sue everyone in sight.

Bill

Somebody will probably trip over it so you'll never find out. And you'll probably end up getting sued!

Ooh ooh! Where can I get a little four-step escalator for my living room?

This is misuse of a Slinky. A Slinky should be stretched out with a transducer at each end and used as a "spring reverb."

-----

I've actually seen a two-platform slinky driver (slinky permanently attached on each surface), and it just pumps back and forth incessantly ;-)

...Jim Thompson

Good question!

I suspect that curving the stair surface can make it laterally stable.

: >>On Sat, 6 Mar 2004 13:23:31 -0500, "Bill Garber" : >> wrote: : >>

: >>>Or turned off, or moving too slowly. : >>>

: >>>Lots of variable left out Jim. I sort of : >>>remember you complaining about people doing : >>>that with your classroom tests here. 8o) : >>>

: >>

: >>It's a question "for discussion" ;-) : >

: >

: > More of a "thought-provoking metaphysical conundrum" IMV. :-) : : Hang on -- a conundrum is a riddle in which a fanciful question is : answered by a pun. Like: : : "How is a cat's tail like a long road?" : : "Because they are both `fur' to the end." : : We got the fanciful question part. Now we need the punnish answer. : /Then/ we'll have a conundrum.

Jim, can you "spring" into action here before it "escalates", or will you try to "slink" out of it. LMAO! (as I duck and run)

Bill @ GarberStreet Enterprizez };-) Web Site -

: >Ooh ooh! Where can I get a little four-step escalator for my living room? : : I've actually seen a two-platform slinky driver (slinky permanently : attached on each surface), and it just pumps back and forth : incessantly ;-) : : ...Jim Thompson

Jim,

I have the correct response to your question as it was notibly worded and undiscovered by all to this point. The answer is NO!, it can't, as it was only "placed" onto the escalator it will eventually reach the top or the bottom depending on which escalator it is "placed" onto. Now what do I get? Heh Heh! You never mentioned that the Slinky was set to motion.

Bill @ GarberStreet Enterprizez };-) Web Site -

I'll do my best !-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

Right here:

But I think the steps only go down, you may have to modify it so the steps go up, to keep your Slinky in tip-top stair-descending shape.

-----

The hard part is digging out the big basement to store all the steps.

There is exactly the right escalator at Gdansk airport, it stops 1 run + 7 steps over when someone gets on at the bottom so provided the slinky can move 7 steps in this time period it should run forever (all other variables sorted). It's sad what one does when waiting for a plane.

Who is going to try it?

It can also be made to shimmy using several amps of pulsed current.